Barrier systems have a variety of uses in a wide range of industries. Their uses include: protection of soil from water or wind erosion, protection of crops and plants from wind, sand trapping for dune or beach development, dust control, snow fences, livestock fences, water diversion, berms for storage of water or other liquids, silt fences and canal systems for water transport or liquid waste transport.
The design of such barrier systems depends to a large extent on their application. For example, sediment control barriers include the use of straw bales secured end to end and to the ground perpendicularly across the flow of water, sand bags piled on top of each other and aligned end to end perpendicularly across the flow of water, various kinds of log and stone barriers, cross trenches, terraced slopes, various kinds of concrete structures and gabions.
Sediment control barriers also include filter fences, constructed of filter fabric, posts and wire fences. These are single vertical barriers made from a fabric supported in an upright position by posts and support mesh. Another design is a brush filter barrier made from a filter fabric draped over a brush barrier.
Another kind of barrier used for erosion control includes a matting or blanket, for example a weaved matting, placed directly on the ground. Small grains or grasses grow up through the weave of the matting to form the barrier. Such a flexible fabric blanket or mat is disclosed in U.S. Pat. No. 4,292,365 (Kane et al). In an alternative form, the flexible fabric blanket may be wrapped around itself and placed vertically upward in a ditch to form a 3-ply vertical barrier.
A further use of barriers is for snow fencing. U.S. Pat. No. 4,339,114 (Dieke), discloses a snow fence made of a framing structure for supporting a fence face between spaced upright members. A mesh is placed over the frame, and angled supports on the leeward side of the fence support the fence. The angled supports attach to the upright posts at intermediate points on the upright posts.
These barriers suffer from certain disadvantages. The snow fence described in U.S. Pat. No. 4,339,114 (Dieke) is complex and expensive to build. For use in roadside erosion control applications, hay bales suffer the disadvantage of quickly disintegrating, rock piles and other rigid barriers are dangerous to motor vehicles that leave the road, and vertical fences are difficult to maintain, in that they tend to collapse under the weight of sediment.
U.S. Pat. No. 5,039,250 (Janz) discloses a barrier system for installation adjacent a roadway, which barrier system is comprised of a permeable sheet having a unitary structure and being folded about a longitudinal axis to form an apex, the permeable sheet having an upslope side and a downslope side and being transversely stiff at least on either side of the apex, and having first and second longitudinal edges on the upslope side and the downslope side, at least the longitudinal edge on the upslope side being secured in the ground, and the permeable sheet having a mesh size selected to discriminate against a chosen size of particles, whereby the mesh sheet is collapsible under the weight of impact of a vehicle.
The barrier system disclosed in U.S. Pat. No. 5,039,250 (Janz) has enjoyed commercial success and may in fact be retrieved and reused when it is no longer needed in a particular location. However, in some applications, reusing the barrier system is unnecessary or impractical, with the result either that the barrier system is retrieved only to be discarded, or that the barrier system is left in place and effectively becomes waste or garbage and presents an environmental problem.
The present invention is directed at a barrier system of the general type disclosed in U.S. Pat. No. 5,039,250 (Janz) which is constructed of a degradable material which will enable the barrier system to perform its functions during a service life and which will degrade so that the barrier system does not need to be retrieved and so that the barrier system does not present an environmental problem.